1. Field of the Invention
The present invention relates to a zero clearance fireplace of the type usually installed through an exterior wall of a room to be heated. More particularly, the present invention relates to a prefabricated and factory built directvented zero clearance gas fireplace and to a horizontal exhaust pipe system which brings in outside combustion air and reduces the exhaust gas temperatures to below underwriters standards.
2. Description of the Prior Art
The purpose of the present invention is to provide a fireplace which eliminates a conventional masonry or prefabricated metal chimney. Masonry chimneys are usually made with two walls, one of which is an inner tile wall that rises above the highest point of a roof of a house. Masonry chimneys made with an original house are expensive. However, such chimneys are even more expensive when added to a house that is already built. To overcome the high cost of masonry chimneys, prefabricated metal chimneys have been designed such as those set forth in our U.S. Pat. No. 4,424,792. The heater described in this patent is adapted to burn any type of fuel in a free standing heating unit and to cool the hot exhaust gases by mixing outside fresh cool air with the hot exhaust gases before discharging them to the atmosphere. Such free standing heating units require an induced draft system which is mounted on the exterior wall, thus limiting this application to residential or commercial buildings which would permit the installation of a large motor contained box on the exterior wall. Numerous apartment buildings and multi-story condominium buildings have building requirements and zoning requirements which prohibit the installation of an induced draft fan system on the outside wall.
Heretofore, fireplaces have been provided in multi-story buildings by providing a required Class A chimney. Such chimneys require either a triple wall, double wall or insulated wall type installation. These Class A chimneys cannot be economically installed in a newly built building or retrofitted into an existing multi-story building. The lowest cost such retrofitted chimney would be a prefabricated chimney. If such a prefabricated metal chimney is installed through the ceiling of a room and eventually through the roof of a highrise building, there arise numerous problems requiring cutting through numerous ceilings and the roof and then providing special flanges and/or adaptors and flashing in order to seal against leaks. When such prefabricated metal chimneys are built into an interior room of a multi-story house, the clearance between the flammable ceiling and the roof structure becomes critical because the metal chimneys are often operated at a temperature which often rises above the kindling temperature of the adjacent structures.
Another problem associated with installing fireplaces in multi-story buildings is that when using gas as a fuel, the air for combustion of the gas must be supplied from some source other than the room being heated, otherwise, the oxygen levels in the room are depleted to an unsafe level by underwriters' standards.
It would be extremely desirable to provide a prefabricated structural fireplace which eliminates the aforementioned problems associated with conventional chimneys and gas fired burning fireplaces. It would be extremely desirable that the fireplace be economical to build and economical to install while providing extremely high burning efficiency and while meeting the safety and environmental standards associated with installation of a fireplace in a highrise or multi-story building.